FIELD OF THE INVENTION
The invention relates to a method for controlling a hydraulic drive for an electrical power circuit breaker and a configuration for carrying out the method.
As is known, such a drive is disclosed in Publication No. DESAN 1008 92 D dated March 1992 of the firm ABB Schaltanlagen GmbH.
If it is desired to increase the circuit-breaking capacity of the electrical circuit breaker, a correspondingly higher mechanical circuit-breaking power must be provided by the drive of such a device. Two methods are essentially available to make the existing drive capable of that operation. Thus, operating the drive with an increased pressure difference of the working fluid could be considered, but that requires a material outlay which is no longer acceptable.
On the other hand, larger valve cross sections could be chosen, in particular, in order to allow more working fluid to flow out of the piston/cylinder system per unit time during circuit breaking. That necessitates more powerful circuit-breaking solenoid coils which are not obtainable commercially. The provision of a second, parallel valve seat, which would have to be capable of being driven by a further solenoid valve, would therefore be conceivable. Since the circuit-breaking solenoids are always kept available in duplicate form for safety reasons, that solution implies an increase in cost which is not insignificant. Added thereto are increased outlays for electrical conductors and control devices, and the provision of a correspondingly larger battery power.